Every year, one hundred million tons or more of vegetable fat or oil is used around the world for foods such as margarine, shortening, dressing, and hydrogenated edible oil, for fuels, or for industrial use such as lubricating oil or raw materials of surfactants. Due to the increase in the world population or the like, a demand for the vegetable fat or oil keeps increasing. The production of vegetable fat or oil focused on palm oil and soybean oil increased by about 1.5 times between 2001 and 2008. It is considered that the increase in production may result from the promotion of forestation, breed improvements, and the like in the main production areas such as Malaysia or Indonesia, or may be greatly affected by policies including grants that are implemented as the use of biodiesels is increasing, particularly in Europe.
However, for example, regarding palm oil or coconut oil, the area where the plants can be cultivated is limited to a partial area such as Southeast Asia, and biological diversity has to be protected. Because of these issues, it is not desirable for expansion of plantations due to deforestation, and there is a demand for increasing the production of fat or oil per unit plant.
Under the circumstances described above, the inventors of the present invention have developed a method for manufacturing vegetable fat or oil by using plants cultivated in a phosphorus-deficient state or plants suffering from phosphorus deficiency (PTL 1). Furthermore, the inventors have developed a method for manufacturing vegetable fat or oil by cultivating mutated plants in which starch biosynthesis is inhibited (PTL 2).